Metal lamppost in garden... TNC-S

[westward10]

Run swa to the lamp post (volt drop calculations) bonded on a 30MA rcd in the consumer unit job done!

Why would it require rcd protection.

 

[westward10]

The post will propably act as one big rod.

This was suggested many years ago by the ILE but was felt the column would be unreliable as an electrode due to corrosion, protection on the column to prevent corrosion and the means of bedding it in the ground.

 

[weevilward]

Why would it require rcd protection.

It doesn't need RCD but it wouldn't hurt to have it.

This was suggested many years ago by the ILE but was felt the column would be unreliable as an electrode due to corrosion, protection on the column to prevent corrosion and the means of bedding it in the ground.

Yeah this one is pretty rusty!

 

[weevilward]

This is probably a case of minimal risk. In general you are not constantly handling a lamppost, as opposed to hand held electrical equipment, and so the risk of neutral loss fault occurring and it being a risk due to contact are low.
Bonding will have limited effect since the potential you are trying to eliminate is between earth and the supply and bonding will only limit the PD between the MET and the supply.
Within a property there should be no potential differences because the bonding connects all sources of potential difference together. Outside a property without installing conductive mats in the ground you cannot avoid being in the presence of a nominal 0V from true earth and so the risk is increased.

Thanks Richard, this makes sense.

 

[Paul mccullagh]

I would personally protect this with a rcd due to someone dismantling fixtures and changing a light bulb!

 

[Deleted member 9648]

Well you cud'a knocked me down with a feather when I saw this, normally it's only sheds that bring people out in a cold sweat when TNCS is mentioned. I think I've pointed out before that those who come over all unnecessary at the mention of a shed never seem to get that queasy feeling with other outdoor installs.
So good on'yer Weevilward, shows you are thinking about what you are doing rather than just following the herd and subscribing to myths.

 

[static zap]

Is it the tallest piece of garden furniture , on a Hill Top !
(that's the other kind of rod ! )

 

[weevilward]

Ha ha, no it's not the tallest thing by a long shot...
Redirect Notice - https://goo.gl/images/RszhTX

 

[stevethesparks]

How many people think to make their outdoor socket TT, whats the difference?

 

[dmxtothemax]

If you have any concerns over safety,
then simply fit an RCD inside the house
this will not only protect the post but also the wiring to it.
you can never be too safe